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Assessing Contaminant Sensitivity of Endangered and Threatened Aquatic Species: Part I. Acute Toxicity of Five Chemicals
Citation:
Besser, J. M., N. Wang, C. G. Ingersoll, F. J. Dwyer, AND F L. Mayer Jr. Assessing Contaminant Sensitivity of Endangered and Threatened Aquatic Species: Part I. Acute Toxicity of Five Chemicals . ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 48:155-165, (2005).
Impact/Purpose:
To determine the chronic toxicity of copper and pentachlorophenol to 2 endangered species and 2 surrogate fish species
Description:
Early life-stage toxicity tests with copper and pentachlorophenol (PCP) were conducted with two species listed under the U.S. Endangered Species Act (fountain darter, Etheostoma fonticola, and spotfin chub, Cyprinella monacha) and two surrogate species (fathead minnow, Pimephales promelas, and rainbow trout, Oncorhynchus mykiss). Results were compared using lowest-observed effect concentrations (LOECs) based on analysis of variance (ANOVA) and by point estimates derived by linear interpolation (ICp), and logistic regression (ECp). Sublethal endpoints, growth (mean individual dry weight) and biomass (total dry weight per replicate), were usually more sensitive than survival. The biomass endpoint was equally sensitive as growth and had less among-test variation. Toxicity thresholds based on linear interpolation were less variable than LOECs, which corresponded to effects ranging from 9% to 76% relative to controls, and were consistent with thresholds based on logistic regression. Fountain darter was the most sensitive species for both chemicals tested, with thresholds for toxic effects on biomass at 10 ug/L or less (LOEC and IC25) for copper and 21 ug/L (IC25) for PCP, but spotfin chub was no more sensitive than the surrogate species. Toxicity thresholds for fountain darter were lower than current chronic water quality criteria for both copper and PCP. Protectiveness of chronic water quality criteria for listed species could be improved by the use of safety factors or by conducting additional chronic toxicity tests with specific listed species and chemicals of concern.